Solid waste treatment system

ABSTRACT

A method for composting solid waste material wherein, in initial treatment stages an optimum particle size is developed at a comminution station. Following an initial air classification arrangement, heavy inorganic materials are segregated to the extent that aluminum, glass and paper characterized products are removed for recycling purposes. A characterizing feature of the invention resides in the development of an optimized moisture content or digestible classified size optimized material at a relatively early stage prior to maceration developing a pulpous substance for digestion. A pug-mill arrangement is utilized for adding optimized moisture prior to digestion and maceration and a cage mill is utilized for the maceration stage of the process.

PRIOR CASE

This is a continuation of the application Ser. No. 969,281, filed Dec.13, 1978, now abandoned, which, in turn, is a division of applicationSer. No. 728,188, filed Sept. 30, 1976, now U.S. Pat. No. 4,134,731.

BACKGROUND

Controlled composting procedures have been proposed over the past forthe purpose of providing an improved disposal of municipal refuse,sewage, sludge, plant waste and similar biodegradable materials. Theadvantages attendant with this form of treatment are manyfold, forinstance, the compost or end product of the procedures not onlyrepresents a significant reduction in waste volume, thereby minimizingland-fill disposal needs, but also, may represent a product ofsignificant commercial value as a carrier, inert or otherwise, for awide variety of products including fertilizers and the like.

Certain of the digestive systems heretofore proposed look to multi-phaseprocedures of decompositions. For instance, in one arrangement, asdisclosed in U.S. Pat. No. 2,820,703, the waste materials are caused toundergo a fungal mold action, following which a period whichdecomposition is predominantly carried out by bacteria active in amesophilic phase at temperatures below 45°-50° C. is effected. Generallyfollowing such phase, a period of maximum biodegradation is permitted toensue wherein bacteria in the thermophilic phase at temperatures about45°-50° C. are witnessed. These multi-phase techniques for wastedecomposition, have been observed to exhibit numerous disadvantages whenconsidered for use in most installations. In this regard, more elaborateplant facilitites are required, pathogens and the like are present inthe noted preliminary digestive phases which lead to health controlproblems. Further, objectionable odors are witnessed.

Proposals for overcoming these disadvantages through the utilization ofsystems operating only in the thermophilic phase and temperature rangehave been propagated, see for instance U.S. Pat. Nos. 3,010,801;3,138,448 and 3,285,732 by Schulze.

The effective maintenance of the thermophilic phase of digestion onscales considered practical for municipal disposal systems however, haveproved to be an involved and difficult undertaking. Not only is itnecessary to assure proper growth of thermophilic bacteria throughmaintenance of requisite incubation temperatures, but also thebiochemical oxygen demand (BOD) of the system must be accommodated foras well as such related pre-digestion process parameters as moisturecontrol, optimum particle size formation and the like. Failure of thesystem to accomodate for any of these parameters results in an outputproduct which is unacceptable both by reason of the failure of acomplete digestion thereof as well as by the opportunity for thecarrying therewithin of pathogenic materials to render the outputuseless for further practical or commercial utilization. Typical of thedigestive systems proposed to accommodate the manyfold difficultiesassociated with large scale waste digestive installations are thosedescribed in Pierson, U.S. Pat. No. 3,523,012 or Hardy, U.S. Pat. No.3,114,622. Generally, the difficulties encountered in the development ofthe systems heretofore proposed appear to have involved a failure ofmeeting the biochemical oxygen demand of the digestive process, failureto maintain necessary temperatures to achieve thermophilic phasedecomposition as well as failure to derive a practical arrangement fordeveloping and maintaining that waste matter water content consideredoptimum to achieve proper digestion.

SUMMARY

The present invention is addressed to an improved process and system forcomposting waste material by aerobic bacterial decomposition.Characterized in providing an optimized pretreatment of solid wastematerials prior to the entry thereof into the region of digestiveactivity, the system achieved improved digestive efficiencies to providecorresponding facility designs of a practical scope suited foraccommodating the large waste volumes encountered in municipal disposalsystems.

As another feature and object, the system and process of the inventionpermits the derivation of highly efficient thermophilic aerobicdigestion by so pretreating solid waste material entering the system asto maximize the receptivity of the treated material to preferreddigestive activity, thereby considerably enhancing digester efficiencyand performance.

With the system, the untreated refuse or starting material initially iscollected in typically random fashion through municipally controlled oroperated agencies and the like and, in random but statisticallydeterminable manner is temporarily retained at a receiving or collectionstation. The interval of retention at such station is so limited as toprevent any significant development of anaerobic bacteria or fungusalong with the unpleasantly odorous by-products and generallyundesirable activity thereof. To control such of these environmentalodors as occur, a pick-off arrangement is provided to circulate andconvey the air of the immediate surroundings within the receivingstation to a later-stage digestive process. From the receiving andcollection station, the starting material is moved within the systemthrough a bulk input flow control arrangement, the transfer rateestablished thereby generally regulating the ultimate output of thetreatment system. There follows the carrying out of a function typicallydenoted as "picking" wherein large component non-digestible refuse suchas large appliances, automobile tires, and the like are removed fordisposal in land-fill areas. With the removal of these materials, aprimary comminution stage is provided which serves to reduce the bulkstarting material to a maximum piece or particle size suited both tofacilitate recycle separation stages, for instance the removal offerrous metals and plastics as well as deriving an efficient particle orpiece size to permit an efficient carrying out of later stages involvingmoisture addition as well as maceration.

The output of this primary comminution stage, now referred to as acomposite segregative and size limited material, is passed through theabove-noted separation or classification stages. These stages may bedeveloped to recover valuable materials such as ferrous and non-ferrousmetals as well as glass and paper. Material from the recycle separationfunctions exits as a digestible-classified, size optimized material.This material is moved into a moisture and material consistencyoptimization function within which a moisture content analysis of thematerial is made following which it is introduced to a retention andagitation stage along with that quantity of moisture required foroptimized subsequent maceration and digestion. This retention andagitation stage is provided, preferably through the utilization of a pugmill to assure a thorough absorption by the size optimized material ofthe added moisture.

From the retention and agitation stage, the moisture and size optimizedmaterial is introduced to a macerator stage which serves to convert thismaterial to a pulp-characterized moisture-optimized material ideallysuited for aerobia thermophilic phase digestion. The macerator stagepreferably and uniquely is provided as a cage mill which, when utilizedwith the moisture and size optimized material, provides an ideal pulpousoutput of the correct moisture content to permit aerobic digestionfunctions to be carried out in the most efficient and economical manner.

A characterizing feature of the invention resides in the above-notedprovision of an optimized moisture content for thedigestible-classified, size-optimized material within the treatingprocess at a relatively early stage. By establishing this optimummoisture at an early stage through retention and agitation within a pugmill type device, the next succeeding pulp developing requirement iscarried out in a much more efficient and economical manner. Forinstance, syneresis phenomena normally encountered by the addition ofmoisture required as an adjunct to a conventional second grinding stageprocedures are essentially eliminated with the technique of the instantinvention. The final particle formation of pulping stage, in the presentinvention provided as a macerator stage, requires no excess amounts ofwater to effect the development of a pulp consistency from sizeoptimized material. Not only is the disposal of such extraneous liquidsor liquors an important and serious drawback to systems heretoforeproposed, but there usually has been required a separate stage forremoving moisture from the resultant pulp to achieve moisture contentproper for aerobic digestion. These somewhat inefficent and complexstages are eliminated and the pulp-characterized moisture-optimizedmaterial developed for introduction to the digestion stage are of animproved quality.

A particular object and feature of the invention is to provide a methodand system for composting waste material wherein the pre-treatment ofstarting material includes not only a primary comminution stage fordeveloping an initial optimum size for the material as well asseparation stages for the removal of non-digestible material, butadditionally the utilization of steps and stages wherein a sizeoptimized and digestible classified material is adjusted to propermoisture content at an early stage of the process through submission toretention and agitation. The output of the retention and agitationstages then is introduced as a moisture and size optimized material to amacerator stage which evolves a pulp-characterized moisture-optimizedmaterial uniquely suited for highly efficient aerobic digestion.

Another object and feature of the invention is to provide a process andsystem for treating solid waste material wherein following thepretreatment of starting material, including a comminution stage as wellas a stage and step for removing ferrous metal, a segregation procedurewherein classification is provided such that heavy characterizedinorganic material is removed and further segregation is provided toderive aluminum and glass materials for recycling utilization. Whenremoved by segregation, the materials are selectively introduced into aheating stage wherein any organic residues removed therewith are, ineffect, eliminated.

As another feature and object, the invention provides for the separateremoval of plastic characterized materials as well as papercharacterized materials through a series of steps including theabove-noted air classification to segregate both paper and plasticfollowed by the introduction of segregated materials in moistened formto aspirator stages which serve to segregate the paper from plastic.Following such segregation, the paper is dried and, accordingly, madeavailable for recycling.

Other objects of the invention will, in part, be obvious and will, inpart, appear hereinafter. The invention, accordingly, comprises thesystem and process possessing the construction, steps and procedures,combination of elements and arrangement of parts which are exemplifiedin the following detailed disclosure.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B represent a block logic flow-type diagram showing stepsand components of the system and process of the invention;

FIGS. 2A-2D, when arranged and considered as shown in FIG. 4, provideschematic and pictorial representative of a facility incorporating thesystem of the invention and suited for carrying out the process thereof;

FIGS. 3A and 3B, as arranged as shown in FIG. 5, provide a schematic andpictorial representative of portions of the facility of FIGS. 2A-2D,revealing an alternative embodiment thereof;

FIG. 4 is a diagram showing the arrangement for associating FIGS. 2A-2D;

FIG. 5 is a diagram showing the arrangement of FIGS. 3A and 3B;

FIG. 6 is a sectional and more detailed view of the air classificationarrangement of FIGS. 2B and 3A;

FIG. 7 is a sectional and more detailed view of the pug-mill andcage-mill arrangement revealed generally in FIG. 2B; and

FIG. 8 is a sectional view of the cage-mill arrangement shown in FIGS.2B and 7.

DETAILED DESCRIPTION

The present invention is particularly concerned with those stages andprocedures of a solid waste treatment system and process which serve toprepare starting materials so as to achieve highest efficiencies at thedigesting stage, a stage which may be considered as essentially the lastwithin the process. The waste product, treated according to the instantteaching, entering this final step may be designated as apulp-characterized moisture-optimized material which is ideallyrespective to bacterialogical breakdown within an aerobic thermophilicdigestive phase. In the discourse to follow the principal stages of thesystem and steps in the process which achieve this desired end resultare identified. Additionally, desirable supplimentary stages which maybe incorporated within the system are detailed. To facilitate thedescription, a block flow logic diagram is provided in conjunction withFIGS. 1A and 1B to reveal the process aspect of the invention, asrelated to the stages and their components, particularly, as suchfunctions may be varied or expanded to meet designated facilityrequirements.

Locking to FIG. 1A, the initial steps and stages of the invention arelabeled as having the function of "Starting Material Treatment and BulkInput Control". As is revealed at block 10, solid waste material, orcomposite starting material, is introduced to a Receiving Station, inthe usual random fashion by municipal and commercial collectionagencies, where it is retained for a short interval, for instance 24hours as a general average. The receiving station serves both theobvious purpose of providing a point collection as well as the purposeof contributing to the provision of a desirable continuous type flow ofwaste material into the treating system. The receiving stationpreferably is covered in somewhat general fashion, inasmuch as thosematerials which are collected may exhibit an unpleasant odorouscharacter due to characteristic lower temperature development of fungusas well as anaerobic, for instance, mesophilic phase bacterial activity.A pick-off of the atmospheric air within the environment of station 10is represented by line 12 and labeled as leading to a digestor. FromReceiving Station 10, the material is moved in a manner providing a bulkinput flow control to the system, as represented by block 14, followingwhich it is subjected to an initial "Picking" operation, as representedat block 16, wherein, as shown by line 18, large component,non-digestible refuse is removed. Such refuse may include such elementsas rejected vehicular tires and relatively large metallic objects, i.e.discarded appliances and the like. Following the Picking stage of theprocess at 16, the starting material is introduced to a PrimaryComminution stage represented by block 20. A feedback signal line 22extends from Communition Stage 20 to bulk input flow control function 14to avoid overloading the system at this point in the process.

Looking additionally to FIG. 2A, the process stages and functions thusfar described are pictorially represented. Here, the receiving stationis shown to comprise one or a series of live bottom receiving hoppers 26into which refuse or starting material is dumped or deposited.Generally, these hoppers are formed having canted or sloping sidesurfaces such that the starting material is urged by gravity to migrateto the lowermost surface thereof, which is present as an apron feeder 28extending between drive rolls 30 and 32. Generally, such apron feedersconsist of two strands of roller chain between which are boltedoverlapping double beaded steel pans provided with steel ends, thusforming a continuous moving trough. As is apparent, rotation of therolls 30 and 32 provides for a progressive movement of refuse along thebottom portion of the hoppers to commence an initial bulk movement ofmaterial into the system. As the material reaches roll 32 of feeder 28it drops upon the input end of another apron feeder 46 extending betweenrolls 48 and 50. Thus configured, feeder 46 elevates the startingmaterial from hopper 26.

While an initial or rough input flow central is achieved through therate of operation of feeders 28 and 46, a refinement over such bulkcontrol is provided by a level regulating feed device representedgenerally at 52. Device 52 includes a conventional carrier web or belt54 suspended between drive roll 56 and roll 58. Roll 56 is axially fixedin space, while roll 58 is mounted for movement about the pivot definedby the axis of roll 56. In this regard, a common screw-type elevatingdevice, represented generally at 60, is provided which is coupled withthe supporting axle of roll 58 and which is manually or automaticallyactuable to move the level of roll 58 in an arcuate or generallyvertical direction. Note that roll 58 is positioned with respect to thematerial carrying side of the belt of conveyor 46. Accordingly, shouldthe bulk material traveling upon the upward side of conveyor 46 exceed alevel predetermined by the adjustment of elevating device 60, the web 54of device 52 will remove such material exceeding that height and returnit to the general environment of hopper 26. For this purpose, the belt54 of carrier 52 is shown to extend rearwardly over the upper portion ofhopper 26.

As the material moves upwardly and reaches roll 50 of feeder 46, itdrops upon the entrance side of a vibrating feeder and screener 34.Feeder and screener 34 is configured incorporating a perforated plate,shown schematically at 36, an exit side 38 and a gravity feed outputport 40. The feeder and screener 34 is mounted so as to slope downwardlyfrom its input side and for vibration from an eccentric arrangement 39.Accordingly, upon the vibration of the device and, in turn, ofperforated plate 36, the bulk material deposited thereupon will beagitated at a predetermined frequency and as a consequence, move downthe inclined plane defined by plate 36 to effect a segregation of gritand loose sand which will exit through output 40 to fall upon a conveyor42 for land fill disposal. The thus initially treated remaining materialwill fall from exit side 38 of feeder and screener 34 to be collected byan endless belt or conveyor represented generally at 76.

As alluded to earlier, station 10 preferably is enclosed to confine thegeneral atmosphere surrounding the receiving hoppers 26. Such anenclosure or building is represented somewhat generally at 65 and isshown to include a plurality of ports or doors 68 providing access fortrucks delivering bulk material. Additionally, the building 65incorporates an air removal duct, as is represented generally at 70.Duct 70 will be seen to provide a vacuum outgasing function and the airevacuated therethough is, itself, processed within the digestivefunction of the system to eliminate any objectionable odors whichotherwise might be released to the general environment surrounding thefacility.

As an example of the scale involved in the design of the hoppers andconveyors heretofore described, the total refuse estimated from apopulation of 500,000 served by the treatment facility generally wouldutilize four receiving hoppers 26 having 200 ton capacities, while thevibrating feeder and screeners would be selected, for instance, toremove approximately 10 tons per day of grit and loose sand. Apronfeeders, as at 28, for each of the receiving hoppers 26 would bedesigned to move solid waste at a rate of about 50 tons per hour.

Bulk input flow control being asserted and screening having been carriedout, the material exiting from side 38 of screener 34 is deposited ontoan endless belt, designated generally at 76 serving to expose the refusedeposited thereon for the earlier denoted picking function described inconjunction with block 16. The picking belt 76 extends between driverolls 78 and 80 and is supported in a generally horizontal orientation.As large component type, non-digestible refuse is identified on thebelt, it is removed manually or by appropriate picking devices, placedupon conveyor 42 and ultimately disposed of in land fill or othersuitable large bulk disposal facilities. If desired, some smallerparticle size ferrous metal refuse may be removed at this stage oftreatment by providing a magnetic type head pulley at 80. Inconventional fashion, the magnetized heat at 80 would attract suchferrous metal particles just long enough to deflect their fall along avector direction displaced from that exhibited by the non-ferrous metalmaterials exiting from belt 76. However, in the arrangement nowpresented, such metal removal preferably is provided at a later stage inthe process.

Upon undergoing picking treatment at belt 76, bulk waste materials isdeposited from over roll 80 into a primary comminution stage,represented by a crusher 86. Comminuter function 86 serves to reduce themaximum average particle size of the bulk material passing therethrough.Preferably, this size will provide a maximum average effective diameterfor the particles of about 6 inches. A reject port for crusher 86 isrepresented at 87. The term "effective diameter" is considered to bethat diameter of a hypothetical circular section of a particle having asurface area the same as that sectional area of a corresponding normallyencountered particle of irregular shape. This maximum average particlesize is selected both to facilitate later classification of materials aswell as to establish that particle size within which moisture levelsrequisite optimum for both pulp formation and digestion may bedeveloped, as discussed in detail later herein. Devices as at 86generally operate utilizing horizontally rotating crushing componentswhich, in addition to developing the noted bulk particle size alsoreject materials of excessive size and density. Such rejected materialsmay, for instance, be removed to a land fill as by conveyor 42. Typicalof crushers utilized as at 86 are those identified under the designation"Eidal"-type Grinder, marketed by The Carborundum Co. of Hagerstown, Md.

The earlier noted feedback signal, described in conjunction with FIG. 1Aat line 22, may be derived through typical control techniques i.e.current load monitors and the like associated with the drive componentsof device 86. By monitoring such loads, comparing the resulting signalswith a desired control level and deriving an output signal, an automaticcontrol input can be asserted at elevating device 60 to adjust bulk flowinput to the remainder of the processing system. Alternately, feeder 28and/or conveyor 56, feeder 34 and belt 76 may be temporarily haltedunder overload conditions.

Looking additionally to FIG. 2B, material exiting from primarycomminution stage 86 now may be referred to as a "Composite Segregativeand Size Limited Material" and is droppd by gravity upon the lowermostside of a conveyor represented generally at 90. Formed as a continuousbelt 92 extending between terminally disposed drive and idler rolls,respectively shown at 94 and 96, the noted Composite Segregative andSize Limited Material is elevated for entrance to the next processingstage of the system. To facilitate deposition from grinder structure 86,a small hopper 96 is provided at the entrance to conveyor 90. At theuppermost roll 96 of conveyor 90, the Composite Segregative and SizeLimited Material encounters the first of a series of Recyclable MaterialSeparation Stages, which are generally outlined under that label in FIG.1A. Looking to the latter figure, it may be observed that Ferrous MetalRemoval is carried out within the initial stage of treating the sizelimited material, as revealed at block 104. Such ferrous material isrecoverable and of value in recycling procedures. Accordingly, thedisposition thereof is represented at 106. Following this initialferrous metal removal, the size limited material is directed through aseries of air classification operations which, according to designoption, may be provided for removing a corresponding series ofmaterials. These operations are functionally associated in that an airclassification technique is utilized to effect select material removalbasically in dependence upon the known densities exhibited by theirconstituent makeup. The air classification function is representedgenerally by block 108, which reveals that heavy inorganic materialsinitially are removed. These heavy inorganic materials will include, forinstance, glass, aluminum and rock and non-recyclable refuse which willhave been carried through the process to that point. Generally, aGravity Separation stage or stages is provided to further segregate theinorganic materials, as is revealed by block 110. Shown extending fromblock 110, as being segregated by type gravity device, are glass,aluminum and rock. Where desired, the glass segregated output furthermay be classified to derive a collection of clear or flint glass as wellas pigmented glass.

Following the removal of heavy inorganics, as revealed at block 112,moisture may be added to the materials remaining within the airclassification stages for the purpose of segregating plastics and paper.The amount of moisture added is only that required to contributesufficient density to the paper material as to render it identifiableover conventional plastics for purposes of air classification. It isimportant to note that the amount or content of water absorbed by thematerial particles at this stage of the process preferably is less thanand not more than equal to that content of water considered optimum forfinal digestion. Accordingly, following the addition of moisture as atblock 112, plastics, not absorbing the moisture, are removed fromclassification function 108 to be directed to a Cyclone Separator stage,as revealed at block 114, from which it is directed to a baler function116 for disposition in accordance with the desires of the operator.Similarly, paper may be removed from the classification function 108following plastic removal and directed to a drier, as represented atblock 118, to remove the earlier induced moisture and providesterilization and thence directed to a baling function as shown at block120. The percentage of paper removed during air classification may beselectively variable in dependence upon the sophistication of the airclassification function designed for a particular installation. Inasmuchas paper, in and of itself, is a digestible material, where its value asrecycled and baled is sufficiently high, a correspondingly highpercentage removal is economically justified. However, as labeled inFIG. 1B, the material derived from function 108 may be categorized as a"Digestible-Classified, Size-Limited Material".

Returning to FIG. 2B, as conveyor 90 elevates the composite segregativeand size limited material to the vicinity of its terminus at roll 96, itencounters the region of magnetic field influence asserted from aferrous metal removal stage, revealed generally at 126. Stage 126 isshown to comprise a relatively large electromagnet, represented by block128, which is supported within a belt conveyor including terminal driverolls 130 and 132 and conveyor belt 134. Magnet 128 is configured andpositioned to develop its magnetic field in close adjacency andcontinuously along the lower disposed surface of belt 134. Extendingbeneath belt 134 in the vicinity of roll 132 is a conveyor,schematically represented at 136. Accordingly, as materials carriedalong belt 92 move into the vicinity or region of magnetic influence ofmagnet 128, they are attracted to the externally exposed side of belt134 by virtue of the magnetic influence and are carried thereby undersuch influence until the belt encounters roll 132. This position uponthe belt being without the magnetic influence magnet 128, the materialfalls by gravity to conveyer 136, whereupon it is conveyed to a storageregion for ultimate disposition as a valuable product of the system.

Ferrous metal particles having been removed, the remaining size limitedparticulate material falls into the entrance hopper 140 of an airclassifying aspirator 142. Aspirator 142 serves to segregate heavyinorganic particles, such materials, as described above, includingglass, aluminum, rock and non-reclable refuse which may have beencarried to this stage in the treatment system. As is revealed in moredetail in FIG. 6, aspirator 142 includes an entrance or connectivecollar 144 coupling its uppermost input with hopper 140. Collar 144addresses a generally downwardly disposed chamber which is bifurcate atits lowermost portion to define two channels intended for a combinedgravitational and dynamic separation of materials. One such channelprovides a more or less direct drop, or purely gravitational vectororientation, exiting at an outlet 146. The other chamber, extending fromthe common entrance area of the aspirator is revealed generally at 148,extends along a somewhat deflected vector path to a correspondingoutlet, represented at flange 150. Formed outwardly from common area 148and extending downwardly toward outlet 146 along one side of aspirator142 is a rectangularly shaped plenum 156 which, in turn, is connectedthrough ducting as at 158 including flow control vane 152 to a source ofpressurized air as may be generated, for instance from a conventionalcentrifugal fan. This input of air through a duct as at 158 is revealed,in the interest of clarity, at arrow 154 in FIGS. 2B and 6. Formedinwardly along the open face of plenum 156 is a grate-type baffle,revealed generally at 162. Extending between channel-type frame members164 and 166, baffle 162 is formed of two lattice-type members 168 and170 which may be manipulated with respect to each other to define anarray of openings for dispensing air in uniform fashion within thechamber of aspirator 142 in accordance with the desires of the operator.With the structural arrangement thus provided, particulate materialsentering aspirator 142 through collar 144 will fall under gravity inaccordance with a path determined by their discrete densities. Inparticular, heavy inorganic materials such as glass, aluminum or rockand non-recyclable refuse will follow a purely gravitational vectorgenerally leading to their exit through outlet 146, while lighterparticles, representing plastics and biodegradeable materials, includingpaper will be deflected by the air stream generated from plenum 156 andbaffle 162 to follow a deflection vector causing their exit through theopening defined at flange 150.

As heavy inorganic materials exit through port or opening 146, they fallupon a conveyor, shown generally at 174. Conveyor 174 is representedmore fully in FIG. 2B in altered orientation in the interest of drawingclarity and is there shown to include a hopper portion 176, as well asdrive rolls 178 and 180, provided at the termini of the conveyer andsupporting an endless belt 182. The conveyer 174 serves to move theheavy inorganic particulate matter into the input hopper 186 of afluidized-bed separator revealed generally at 188. Also referred to a"gravity separators" or "air-tables", separators as at 188 are known inthe art, for instance, being marketed by Triple/S Dynamics Corporation,Dallas, Texas, and provide particle separation by a combined action ofgravity, fluidized air, stratification of the material or particles andvibration. As is revealed schematically in FIG. 23, separator 188comprises a chamber 190, supporting hopper 186 and covering a perforatedeck 192 over which the material particles are deposited from hopper186. A plenum 194 is structured beneath deck 192 to provide a lowpressure fluidized air source impinging and passing through the openingsthereof. The air source for plenum 194 is represented schematically byan arrow 196. Deck 192 further is suspended for vibration as well as ina two directional slope orientation by a spring arrangement depictedsomewhat schematically in the drawing at 198 and 200. Vibration may beimparted to the assembly 188 by an eccentric connection with a rotarydrive, as revealed schematically by a rod 206, one end of which iscoupled with plenum 194 and the other of which is connected in eccentricfashion to a rotational drive output represented at 208. Air is removedfrom the chamber or hood 190 through a duct 210.

Material is selectively removed from the separator 188 at a series ofhopper-like devices 214-220, disposed in serial fashion along the lowerside of deck 192. Exemplary of the arrangement described in conjunctionwith air classification function 108 in FIG. 1A, separator 188 operatesto remove rock materials and the like through hopper 214, located at theuppermost level of deck 192. In this regard, a conduit 222, leading fromhopper 214, deposits the rock upon a conveyer or the like, showngenerally at 224, which removes such materials to land fill, forinstance by deposition upon the earlier described conveyer 42. The nextsucceeding hopper 216, positioned along the side of deck 192, serves tocollect glass particles, which are directed through a flexible conduit226 to the entrance of a glass classification device 228. Device 228 isschematically revealed as comprising an input port 230 through whichglass materials are directed. These materials are diverted by a vane 232so as to fall upon a rotating drum 234 at an off-center location. Withinthe drum is disposed in stationary fashion an electro-magnet 236 servingto provide a high intensity magnetic flux along half of its cylindricalarea or extent. As the drum rotates about the magnet 236, clear orflint-type glass immune to magnetic fields, falls along purelygravitational vectors to exit through one outlet 238 of a bifurcateexit. Note that a triangular shaped vane portion 240 is positionedbeneath the center line of drum 234 which serves as a deflecter for theglass particles. Those glass particles which are pigmented,conventionally by the incorporation therewithin of ferrous compounds andthe like, are slightly deflected by the magnetic field extant at thesurface of drum 234 and, in consequence, are sufficiently deflected tofall through an exit or outlet 242.

Hopper 218 may be so positioned along deck 192 as to collectnon-recyclable refuse having a density other than that of rock and thelike. For instance, particles of leather and rubber will be collected athopper 218 to exit through conduit 250. Thereupon, these materials arecarried away by a conveyer 252 to land fill facilities or the like. Asin the case of conveyer 224, conveyer 252 may communicate in materialexchange fashion with conveyer 242.

Looking additionally to FIG. 2D, the lowermost hopper 220 affixed todeck 192 is positioned to receive aluminum particles which are directedtherefrom through flexible conduit 256 to the input hopper 258 of astorage tank 260. Incorporating a typical air relief valve 262 and amaterial release gate 264, tank 260 accumulates aluminum products over aspecified interval of time, whereupon gate 264 is opened to permit theaccumulated products to fall upon and be conveyed by a vibratory feeder266 for metered flow onto a carrier 270, which, in turn, leads to arotating drum drying and sterilizing device 272. Carrier 270 is shown toinclude drive rolls 274 and 276 which contribute to the support of anendless belt 278. Entrance of the material to drum dryer 272 isfacilitated by a hopper arrangement revealed schematically at 280. Insimilar fashion, the pigmented glass outlet 242 of device 228 iscollected through the hopper 282 of a storage tank 284. Formed insimilar fashion as tank 260, tank 284 includes an air relief valve 286as well as a release gate 288. Adjoining tank 284 is a similar tank 290,the hopper 292 of which is positioned beneath outlet 238 to provide forthe reception of clear glass particles. Tank 290 is vented at 294 andprovided a release gate at 296 in similar fashion to the arrangementprovided in connection with tank 260. Gates 288 and 296 of tanks 284 and290 are positioned over respective vibratory feeders 298 and 300, inturn, extending to conveyer 270 such that the contents containedtherewithin may selectively be deposited upon the conveyer for deliveryto drier 272 at times deemed appropriate by the operator of the system.Without the vibratory feeder arrangements, loadings transferred byconveyer 270 to drum 272 may be excessive, i.e. these feeders serve tometer the flow to conveyer 270 to provide a regulated input to drier272.

From drier 272, the materials are collected for recycling disposition.From outlet 271 of drier 272 those materials passing through the drierare deposited upon a conveyer as represented generally at 273. Conveyer273 may, for instance, be of the endless belt variety including terminalroll portions as at 274 and 275. The material so deposited upon conveyer273 is moved upwardly for conveying it to a selected one of dispensingbins 276a-275c. This selection is carried out, for instance bypositioning the belt of the conveyer with respect to a diverting plow,as at 277 or 279. By so altering the conveyer belt, for instance, plow279 will divert material into bin 276b, or plow 277 will divert materialinto bin 276a. Gates as at 281a-281c associated with bins 276a-276c maybe selectively released to convey the materials stored therein within amode of conveyance, for instance the truck vehicle represented at 283.

As noted hereinabove, the provision of the separator, device 188 as wellas the storage, glass classification and drying arrangements areoptional to the design of any given facility. Where the characteristicsof the disposed refuse and the value of the reclaimed glass and aluminummaterials are appropriate to the initial capitalization required forsuch facilities, they generally are incorporated within the overallsystem. However, where this is not the case the heavy organic materialoutput issuing from outlet 146 of aspirator 142 are committed toconventional land-fill for final disposal.

Looking to FIGS. 2B and 6, those material particles deflected to exitfrom aspirator 142 through outlet flange 150 pass through a flexibleconnection 310 to an elutriating type air classifier, depicted generallyat 312. Classifier 312 incorporates a series of perforate gratesarranged in descending step fashion, as at 314a-314e, (referred tohereinafter and shown in FIG. 2B as grates 314). Grates 314 arepositioned within a housing, the portion formed beneath the gratesdefining a plenum chamber 316 having an air input collar 318 which isconnected through a flexible connector 320 to an air input ductextending from a fan 160. In the interest of clarity, this air input isrepresented generally in FIG. 2B by an arrow designated 324. The entireclassifier structure 312 is suspended, for instance by springs depictedat 326 and 328, to permit its vibration. This vibratory input isschematically represented by a bar 330 connected between the housing ofthe classifier 312 and eccentrically to a rotational drive 332. As isapparent, this vibrator arrangement will be observed to account for theflexible couplings provided at 310 and 320. Material from aspirator 142is deposited within an upwardly disposed chamber, designated generallyat 334 and, as it enters this chamber, is wetted by water passingthrough nozzles as at 336, (FIG. 6) positioned at an entrance area forthe material. Nozzles as at 336 are coupled through a conduit 338incorporating a value 340 and extending to a water supply generallydesignated at 342. Accordingly, the paper and other materials enteringchamber 334 are dampened and their density is elevated such that underthe above-noted vibration, the dampened paper particles will migratealong grates 314 to an exit port 348, while lighter plastic materialswill be blown by the air-flow through grates 314 to be driven throughserially dispensed louvers 308 and thence through outlet 344.

The lighter particulate materials which are blown upwardly through vanes308 and outlet 344, enter and pass through a conduit 356. Conduit 356 iscoupled to outlet 344 through a flexible connection 358 which serves toaccommodate for the vibratory action of classifier 312. Looking inparticular to FIG. 2B, conduit 356 is seen to extend to the tangentiallydisposed input port assembly 360 of a cyclone separator 362. Connectionbetween port assembly 360 and conduit 356 is provided at mutuallyadjoined flanges shown at 364. Having a generally cylindrical shape witha funnel-shaped lower portion, separator 362 incorporates a centrallydisposed cylindrical plug 366 as well as an exhaust fan 368 mounted atits upward surface. From exhaust fan 368, a conduit 370 extends, forinstance, through an electro-static precipitator or the like (not shown)for final disposal of exhaust air to the atmosphere. The lowermostportion of separator 362 extends to a relatively large diameter conduit372 which, in turn, communicates with the collection chamber 374 of aconventional baler 376. Baler 376 includes a hydraulicly driven piston,represented schematically at 378, and a baling or wrapping chamber 380.In operation, plastic particles are blown through entrance port 360,whereupon they assume a vortex-type activity about the periphery of thebody of separator 362. As their rotational velocity decreases theparticles bend to move toward the center of the vortex to ultimatelydrop through conduit 372 for baling and disposition.

That material which gravitates along grates 314 and falls through exitport 348 of separator 312 is directed through a flexible coupling andconduit 390 into a next succeeding function of the treatment facility.

Looking to FIG. 1B, such material is now identified as aDigestible-Classified, Size-Limited Material and is labeled as enteringa Moisture and Material Consistency Optimization function. Note that thematerial is of an optimum size for the above-noted classificationprocedures and also for absorbing a predetermined quantity of moisturewhich now is selected to achieve both optimized pulping as well asoptimized aerobic thermophilic phase digestion. Until the present pointin the system, the moisture content of this material is purposelyretained at a level lower than that required for the above treatment.Accordingly, to achieve proper moisture content for theDigestible-Classified, Size-Limited Material, an initial MoistureContent analysis is made thereof, as represented at block 400 in FIG.1B. This analysis, which may be carried out automatically, derives, forinstance, a corresponding signal representative of the amount ofmoisture which must be added to the material to achieve the noteddesirable moisture level. By inserting such signal into a conventionalcomparison network and providing a corresponding error-type mechanicalreadout, a water metering function is readily derived as represented atblock 402. Metering block 402 controls the moisture input to thematerial, as represented at block 404. With the addition of moisture,the Digestible-Classified, Size-Limited Material is retained for aselect interval while being agitated so that the optimized moisturecontent is achieved with assurance that such moisture is fully absorbedthroughout all portions of all particles. It is the intent of theinvention that no excess liquid be generated beyond that required forthermophilic phase aerobic digestion. The important retention andagitation step of the process is represented at block 406 and may becarried out in a pug mill which incorporates water input components.

The material exiting from the retention and agitation stage 406 may becategorized as a Moisture Optimized, Size Limited Material and isdirected to the next succeeding procedure or stage identified at block408 as a Macerator Stage. At stage 408 the moisture and size optimisedmaterial is reduced to a pulpous-like consistency suited for optimizedbiodegradation within the aerobic digestion function of the system.Preferably, a cage mill is utilized for this procedure, the cage millimportantly requiring no excess moisture or the like to achieve the pulpdefining activity required. As labeled in FIG. 1B, the material exitingfrom stage 408 may be defined by Pulp Characterized, Moisture OptimizedMaterial.

This material then is introduced to the aerobic digestion function ofthe system as is labeled and represented at block 410. Aerobicthermophilic phase digestion of the material is carried out under theinfluence of a pressurized air input represented at block 412. Theamount of air introduced is that required to accommodate the BiochemicalOxygen Demand (BOD) of the material to carry out appropriate digestion.Note that this air input utilizes supplementary air picked or removedfrom receiving station 10 which, under anaerobic conditions which mayobtain at such location, can be oderiferous due to the putresciblesgenerated at that early stage of refuse collection. As the digestionprocess is concluded at stage 410, the material exiting therefrom iscooled and dried as at block 414 and a digested output product isavailable from this final Product Treatment function of the system andprocess.

Returning to FIG. 2B and referring additionally to FIGS. 7 and 8, theabove-described retention and agitation stages as well as maceratorstage are set forth in more detail. For instance, conduit 390, carryingthe noted Digestible Classified, Size Limited Material is connected tothe input port 424 of a retention and agitation stage which, inaccordance with the preferred embodiment of the invention, is providedas a pug mill depicted generally at 426. Pug mills, or paddle mixers areutilized in the material processing arts to accommodate requirements formixing, stirring or blending. For instance, they are frequently used formixing mortar, plaster or asphalt materials, or for mixing flue dustwith water as well as in iron sintering and similar applications. Asdescribed in detail above, pug mill 426 serves, in the instantapplication, for generating an optimized moisture content within theparticles introduced thereto. To carry this out, a water source, labeledas such in FIG. 7, is introduced through a metering control representedgenerally by block 432. This water source may be present as aconventional and relatively pure water input or, where the facilitylocation permits, may be present as a water-born sludge. Generally, suchsludge is present as a basically liquid phase carrying about ten-percentby weight solids. Metering control 432 responds to a signal, presentedfrom along line 434, to the signal output of a moisture monitor 436.Monitor 436 is connected through line 438 to a moisture monitoring probe440 which continually monitors the moisture content of materials passingthrough conduit 390 into pug mill 426. This signal is utilized bymonitoring control 432 to regulate fluid input through line 442 to avalve 444. Volume control being effected at valve 444, water then passesthrough conduits as at 446 for dispensation through nozzles as at 448within pug mill 426. In the interest of clarity, only nozzles 448 areshown in FIG. 2B.

Pug mill 426 comprises a generally box-shaped housing, the top andbottom sides of which are represented, respectively, at 460 and 462.Extending along the length of this housing is a centrally disposedrotatable shaft 464 carrying a plurality of serially disposed paddles asat 466. Shaft 464 is rotatably driven through a reduction geararrangement 468 by a motor 470. Accordingly, as Digestible Classified,Size Limited Material enters mill 426 through input 424 thereof, it isprogressively mixed by paddles 466 and gradually maneuvered toward anoutput port 472. By virtue of the mixing activity imparted from thepaddles in conjunction with water input from nozzle 448, and inconsequence of the period of retention established by the length of themill, the material exiting the mill at output port 472 is optimized formoisture content and retains its size-limited characteristic. Thisoptimization of moisture content not only is that most desired forultimate digestion but also, is ideal for the macerating functionimmediately following. Pug mills are available in the market, forinstance, from Link-Belt Company, Chicago, Ill.

As noted above, the material exiting from the retention and agitationstage, categorized as a Moisture Optimized, Size Limited Material nextis directed to a macerator stage. Preferably, this stage is present as acage-mill which is uniquely selected for utilization within the instantsystem. Such mills require no excess moisture or the like to achieve thenecessary pulp formation of the material introduced thereto. Referringadditionally to FIG. 8, cage mill 480 is seen to be enclosed within ahousing 482 the peripheral profile of which is of generally roundconfiguration, being flared outwardly at its connection with asupporting base 484. Somewhat centrally disposed within the housing 482are a series of concentric ring shaped cages as at 486a-486d. Theseindividual cages or cage elements incorporate impact bars, certain ofwhich are identified at 486, which rotate with their associated cagerings. In this regard, alternately disposed ones of the cage rings aredriven from respective opposite sides of the mill. For instance, cagerings 486a and 486c may be driven from a drive input shaft 490, whilecage rings 486b and 486d are driven in an opposite rotational sense by adrive shaft 492. Driving power is supplied to shaft 490, for instance,from a belt or similar transmitting device 494 extending to a powersource, for instance a motor 496. Similarly, shaft 492 may be coupledthrough an appropriate power transmitting device 498 which, in turn, maybe connected to a drive input as from motor 496 or from a separatelydisposed power input as represented at 500.

Moisture-Optimized and Size-Limited Material exiting from outlet 472 ofpug mill 426 enters cage mill 480 through a hopper 506 which serves todirect this material to a generally centrally disposed input opening 508leading to the interior of the innermost disposed cage 486a. Thismaterial impinges upon the cage impact bars 488 thereof and is hurled bycentrifugal force into the path of the counter rotating next outwardlydisposed bars. This multi-stage impaction provides a doubling of theasserted impact force and results in improved product breakdown withminimal mill speed and wear. Upon exiting from the outer cage as at486d, the material falls through opening 510 in base 484. Disposedimmediately beneath opening 510 for receiving the thus dischargedpulpous material is a conveyer, shown generally at 520, comprising aninput hopper 522, terminal end rolls 524 and 526 and belt 528.

Looking particularly to FIG. 2C, terminal roll 526 of conveyer 520extends to deposite the Pulp Characterized Moisture Optimized Materialinto the first cell 540a of a multi-celled digester representedgenerally at 542 and incorporating a successive grouping of cells540a-540e. Material thus deposited within cell 540a commences aerobicthermophilic phase decomposition at appropriate temperature and underproper oxygen input. In the latter regard, air under pressure isintroduced into each of the cells from along the respective floorsthereof through air channels respectively shown at 544a-544c through552a-552c, hereinafter referred to as channels 544-552. Atmospheric airunder pressure is delivered to cells 544-552 from high pressurecentrifugal blowers, one of which is revealed schematically at 554extending through line 556 to an air delivery manifold represented byline 558. Additionally inserted at the intake of blower 554, is theenvironmental air collected from building 66 of the receiving stage andmoved therefrom through duct 70 (FIG. 2A). Upon passing a relief valve560, the pressurized air is maneuvered into branch conduits 562-570,each incorporating a control valve represented, respectively, at582-590.

During the operation of digester 542, material is progressivelymaneuvered from cell 540a through final cell 540e, as it undergoesprogressive decomposition until reaching cell 540e, wherein finaldecomposition and cooling takes place. Upon removal from cell 540e, thematerial is stockpiled for ultimate disposition for instance, thepackaging thereof for resale, use as land fill, or other further productimprovement treatment. This product is referred to as a "Digested OutputProduct".

Turning now to FIGS. 3A and 3B, an alternate association of componentsfor utilization within the recyclable material separation stages isrevealed. In the interest of clarity, where components remain commonwith those described in connection with FIGS. 2A-2D, identicalnumeration providing their identification is retained. In thisembodiment, the general arrangement described in connection with therecyclable material separation stages of the earlier described figuresare provided with certain alterations. For instance in the embodiment ofFIG. 2B, aspirator 142 serves to receive composite segregative and sizelimited materials, having ferrous metal particles removed therefrom,through its entrance collar 144. Heavy inorganic materials are separatedto exit from aspirator 142 through its outlet 146 to be removed byconveyer 174. Corresponding lighter materials, including paper andplastic, are diverted to pass through that channel of the aspirator,having an outlet at flange 150, to enter elutriating type air classifier312. The heavier digestible materials migrate along grates 314 to exitinto conduit 390. Under the influence of forced air, as representedschematically at arrow 324, the lighter particles of the material,including paper and plastics, are blown through vanes or louvers 308 toexit from classifier 312 through its outlet 344 and enter conduit 356.In the instant embodiment, as these combined particles pass alongconduit 356 they encounter the spray nozzles 600 of a pressurized waterinput extending through conduits as at 602 from a pressurized watersupply 604. Note, that no water is added at the classifier stage 312.However, the water now added may be provided in an amount not ascritical as that provided earlier in connection with nozzle 336. Thedampened material particles pass from conduit 356 through connectingflanges, as at 606, to enter an input port assembly 608 of a cycloneseparator, shown generally at 610. Cyclone separator 610 is formed inconventional manner, incorporating an internally disposed plug 612, anexhaust fan 614 and air outlet conduit 616. During operation, wettedpaper and plastic materials enter the separator and assume a vortex formof movement, gradually losing velocity until exiting through outlet port618. Port 618 is connected through coupling flanges 620 to the input ofan aspirator shown generally at 624. Aspirator 624 is configured in thesame manner as that shown at 142 in FIG. 2B and, accordingly, includes aplenum chamber 630 communicating with a supply of pressurized air,depicted only generally by arrow 632. The vertically oriented portion ofthe chamber of aspirator 624 leads to an exit port 634 through whichdampened paper particles exit more or less along a direct gravitationalvector. The lighter plastic particles of the material entering theaspirator are blown through upwardly disposed exit port 636 to passthrough a conduit 638. Connection between exit port 636 and conduit 638is provided by flange coupling 640.

Dampened paper particles passing through exit port 634 are directedthrough a conduit 642 to the feed or entrance hopper 644 of a rotarydrier depicted generally at 646. Drier 646 serves to remove asignificant amount of the moisture content of the paper particles,whereupon the thus dried particles are conveyed by a pneumatic conveyerrepresented by arrow 654 to a storage tank 636 (FIG. 3B). Drying of thepaper particles generally takes place in the presence of atmospheric airand under agitation at an elevated temperature to avoid the occurence ofspontaneous combustion phenomena and the like during storage thereof.Temperatures utilized during this drying step generally are selected asabout 250° F. From storage tank 656, the paper materials pass through aconduit 658 to enter the collection chamber 660 of a paper balerrepresented generally at 662. In conventional manner, as chamber 660 isfilled, a hydraulically actuated piston 664 compresses the collectedmaterial and urges it into a wrapping or baling chamber 666 forrecycling disposition.

Plastic particles passing along conduit 638 are introduced, as in thecase of the embodiment of FIG. 2B, to a cyclone separator representedgenerally at 362. This separator performs in identical fashion as thatdescribed in connection with FIG. 2B. Accordingly, plastic materialscollected are passed through conduit 372 to be baled at baler 376 andappropriately disposed of.

Since certain changes may be made in the above-described system andprocess without departing from the scope of the invention herein, it isintended that all matter contained in the description thereof or shownin the accompanying drawings shall be interpreted as illustrative andnot in a limiting sense.

What is claimed is:
 1. A process for treating solid waste comprising thesteps of:receiving untreated waste material at a receiving station;comminuting said waste material to provide a size limited materialhaving a select maximum average particle size; elevating the moisturecontent of said size limited material by the agitation thereof in thepresence of a select amount of water to provide a moisturized, sizelimited material; controlling the said select amount of water presentduring said agitation and controlling the residence interval of saidagitation to derive a substantially uniform moisture distributionsubstantially throughout all portions of said size limited material ofabout 50 to 60% of the weight of said material; macerating saidmoisturized, size limited material without the further addition ofmoisture by subjecting it to counterrotative beating action to effectbreakdown thereof to derive a pulpous material; and digesting andcomposting said pulpous material by inducing the aerobic decompositionthereof.
 2. The process for treating solid waste of claim 1 wherein saidstep of elevating the moisture content of said size limited material iscarried out with a pug mill.
 3. The process for treating solid waste ofclaim 1 wherein said step of macerating said moisturized, size limitedmaterial is carried out with at least one cage mill.
 4. The process fortreating solid waste of claim 1 wherein said moisture content elevationis carried out by the addition of a select amount of water-born sludgeto said size limited material.
 5. The process for treating solid wasteof claim 1 including the steps of transferring atmospheric air situatein the environment of said receiving station and passing saidtransferred atmospheric air under pressure through said pulpous materialwhile said pulpous material is undergoing said aerobic decomposition. 6.The process for treating solid waste of claim 1 wherein said step ofelevating the moisture content of said size limited material is carriedout with a pug mill.
 7. The process for treating solid waste of claim 6including the steps of transferring atmospheric air situate in theenvironment of said receiving station and passing said transferredatmospheric air under pressure through said pulpous material while saidpulpous material is undergoing said aerobic decomposition.
 8. Theprocess for treating solid waste of claim 7 wherein said moisturecontent elevation is carried out by the addition of a select amount ofwater-born sludge to said size limited material.
 9. A process fortreating solid waste comprising the steps of:receiving untreated wastecomposite starting material at a receiving station; comminuting saidwaste composite starting material to provide a composite, size limitedmaterial having a select maximum average particle size; removing ferrousmetal material from said composite, size limited material; thensegregating by air classification, heavy characterized inorganicmaterial from said composite, size limited material; segregatingaluminum material from said segregated heavy inorganic materialsegregating glass material from said segregated heavy characterizedinorganic material; separately heating said segregated glass materialand said segregated aluminum material sufficiently to substantiallyremove organic material therefrom; controllably elevating the moisturecontent of the remaining said composite, size limited materialsubsequent to said step of segregation by air classification to providea moisture optimized, size limited material having a substantiallyuniform moisture distribution substantially throughout all portions ofsaid material, said moisture content representing about 50 to 60% of theweight thereof said elevation of moisture content being carried out byagitating said size limited material over a residence interval selectedto derive said uniform moisture distribution; and macerating saidmoisture optimized, size limited material without the further additionof moisture by subjecting it to counterrotative beating action to effectbreakdown thereof to derive a pulp characterized, moisture optimizedmaterial and digesting and composting said pulp characterized materialby inducing the aerobic decomposition thereof.
 10. A process fortreating solid waste comprising of steps of:receiving untreated wastecomposite starting material at a receiving station; comminuting saidwaste composite starting material to provide a composite, size limitedmaterial having a select maximum average particle size; removing ferrousmetal material from said composite, size limited material; thencontrollably elevating the moisture content of said composite, sizelimited material to derive a substantially uniform moisture distributionsubstantially throughout all portions of said material, said moisturecontent of about 50 to 60% of the weight thereof said elevation ofmoisture content being carried out by agitating said size limitedmaterial over a residence interval selected to derive said uniformmoisture distribution; segregating, by air classification, heavycharacterized inorganic material from said composite, size limitedmaterial, and, simultaneously, segregating, by air classification,plastic characterized organic material from said composite, size limitedmaterial; macerating the remaining said size limited material withoutthe further addition of moisture by subjecting it to counterrotativebeating action to effect breakdown thereof to derive a pulpcharacterized, moisturized material; and digesting and composting saidpulp characterized, moisturized material by inducing the aerobicdecomposition thereof.
 11. A process for treating solid waste comprisingthe steps of:receiving untreated waste composite starting material at areceiving station; comminuting said waste composite starting material toprovide a composite size limited material having a select maximumaverage particle size; removing ferrous metal material from saidcomposite, size limited material; then segregating, by airclassification, heavy characterized inorganic material from saidcomposite, size limited material, and simultaneously, segregating by airclassification paper characterized material and plastic characterizedorganic material from said composite, size limited material; thenelevating the moisture content of said segregated paper characterizedmaterial and said plastic characterized organic material; thensegregating, by aspiration, said plastic characterized organic materialfrom said paper characterized material; then drying said papercharacterized material by the agitation thereof in the presence of heatand atmospheric air; agitating the organic components of said sizelimited material subsequent to said step of segregation by airclassification and controlling the moisture content thereof by selectmoisture addition to provide a substantially uniform moisturedistribution substantially throughout all portions of said material,said moisture content representing about 50 to 60% of the weight thereofsaid elevation of moisture content being carried out by agitating saidsize limited material over a residence interval selected to derive saiduniform moisture distribution; macerating said size limited materialwithout the further addition of moisture by subjecting it tocounterrotative beating action to effect breakdown thereof subsequent tosaid step of agitation to derive a pulp characterized, moistureoptimized material; and digesting and composting said pulpcharacterized, moisture optimized material by inducing the aerobicdecomposition thereof.